Use of EFG technique to grow a Ga2O3 single crystal is known as a conventional method (see, e.g., PTL 1). In the method described in PTL 1, a Ga2O3 single crystal is grown while gradually widening a width thereof from a contact portion with a seed crystal toward the bottom, i.e., while widening the shoulder, thereby allowing a plate-shaped crystal having a larger width than the seed crystal to be obtained.